IFC (IFC4X3) development IfcSphere Semantic definition

The IfcSphere is a Construction Solid Geometry (CSG) 3D primitive. It is a solid where all points at the surface have the same distance from the center point. The inherited Position attribute defines the IfcAxisPlacement3D and provides:

  • SELF\IfcCsgPrimitive3D.Position: The location and orientation of the axis system for the primitive.
  • SELF\IfcCsgPrimitive3D.Position.Location: The center of the sphere.
  • SELF\IfcCsgPrimitive3D.Position.Position[3]: The z axis points at its positive direction towards the north pole, and by its negative directions towards the south pole.
Figure — Sphere geometry

Texture Use Definition

Textures are aligned facing upright with origin at the back (+Y direction) revolving counter-clockwise. Textures are stretched or repeated to the extent of the circumference at the equator according to RepeatS and RepeatT.

Figure illustrates default texture mapping with a clamped texture (RepeatS=False and RepeatT=False). The image on the left shows the texture where the S axis points to the right and the T axis points up. The image on the right shows the texture applied to the geometry where the X axis points back to the right, the Y axis points back to the left, and the Z axis points up.

Figure — Sphere textures
Side Normal Origin X Origin Y Origin Z S Axis T Axis
Side +Y 0 +Radius 0 (-X, then curving counter-clockwise) (+Z, then curving towards top)
Table — Texture parameters Entity inheritance Attributes

# Attribute Type Description
IfcRepresentationItem (2)
LayerAssignment SET [0:1] OF IfcPresentationLayerAssignment FOR AssignedItems

Assignment of the representation item to a single or multiple layer(s). The LayerAssignments can override a LayerAssignments of the IfcRepresentation it is used within the list of Items.

StyledByItem SET [0:1] OF IfcStyledItem FOR Item

Reference to the IfcStyledItem that provides presentation information to the representation, e.g. a curve style, including colour and thickness to a geometric curve.

IfcCsgPrimitive3D (2)
1 Position IfcAxis2Placement3D

The placement coordinate system to which the parameters of each individual CSG primitive apply.

* Dim IfcDimensionCount

This attribute is formally derived.


The space dimensionality of this geometric representation item, it is always 3.

Click to show 4 hidden inherited attributes Click to hide 4 inherited attributes
IfcSphere (1)
2 Radius IfcPositiveLengthMeasure

The radius of the sphere.

Table Formal representation

ENTITY IfcSphere
 SUBTYPE OF (IfcCsgPrimitive3D);
	Radius : IfcPositiveLengthMeasure;
END_ENTITY; References

Edit on Github

Is this page difficult to understand? Let us know!